Textile manufacturing plants generate large quantities of dust and lint which must be removed from the work environment to ensure worker comfort and safety. Removal is normally achieved by drawing lint and dust containing air from the work area and conveying it through a filtration system where the dust and lint is collected on filters. Normally, the filtration apparatus includes a housing enclosing a plurality of filters and a fan to convey air through the filters. Water spray nozzles may be provided as well. When air passes through the filter surface, lint and dust is deposited on the filter. A particular concern for air filtration systems collecting large particles, such as lint, heavy sawdust and the like, is that larger particles collecting on the filter surface, and in particular, on a pre-filter, tend to clog the surface quickly and thus reduce the filtration efficiency.
One approach to pre-filtering is to provide a roll type filter. A web of filter media initially wound on a first roll is drawn across the filter area. As the filter media web collects dust and debris and the pressure drop across the filter media becomes too great, the filter media web is wound onto a second roll opposite the first roll. Typically, the filter media cannot be reused and is discarded once the initial roll is depleted.
There exists a need for convenient and cost-effective apparatus for pre-filtering air in industrial facilities.